Principal component analysis (PCA) of physicochemical compounds’ content in different cultivars of peach fruits, including qualification and quantification of sugars and organic acids by HPLC

Abstract

The aim of this study was to determine the chemical composition in different cultivars of Prunus persica L. fruits with special focus on polyphenols, carotenoids, sugars and organic acids content. In addition, the PCA model was applied to all data to determine the most important variables that explain the relationships between twenty selected cultivars of peaches and to identify the most attractive cultivars. The conducted study showed that the most interesting cultivars from the point of view of direct consumption are: ‘Early redhaven’, ‘Candor’, ‘Harrow beauty’ due to the large size of fruit, rich juiciness, high maturity index, as well as above-average content of polyphenols and carotenoids. In turn, fruits with medium-sized stones and fruits, a high content of dry matter and total sugars, and with a high content of carotenoids (‘Harrow beauty’, ‘Kijowska wczesna’, ‘Jersey land’), are ideal for the manufacture of healthy dried snacks. Additionally, juicy peaches with a high content of organic acids and bioactive compounds, i.e., ‘WB 258’, ‘Spring time’ and ‘Beta’, are suitable for the production of purees, smoothies, and juices. Finally, it has been shown that peach fruit is an interesting raw material with a varied chemical composition and nutritional value, strongly determined by the cultivar.

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European Food Research and Technology (2019) 245:929–938
https://doi.org/10.1007/s00217-019-03233-z
ORIGINAL PAPER
Principal component analysis (PCA) ofphysicochemical compounds’
content indifferent cultivars ofpeach fruits, includingqualification
andquantification ofsugars andorganic acids byHPLC
PaulinaNowicka1 · AnetaWojdyło1· PiotrLaskowski2
Received: 6 October 2018 / Revised: 27 December 2018 / Accepted: 3 January 2019 / Published online: 18 January 2019
© The Author(s) 2019
Abstract
The aim of this study was to determine the chemical composition in different cultivars of Prunus persica L. fruits with
special focus on polyphenols, carotenoids, sugars and organic acids content. In addition, the PCA model was applied to all
data to determine the most important variables that explain the relationships between twenty selected cultivars of peaches
and to identify the most attractive cultivars. The conducted study showed that the most interesting cultivars from the point
of view of direct consumption are: ‘Early redhaven’, ‘Candor’, ‘Harrow beauty’ due to the large size of fruit, rich juiciness,
high maturity index, as well as above-average content of polyphenols and carotenoids. In turn, fruits with medium-sized
stones and fruits, a high content of dry matter and total sugars, and with a high content of carotenoids (‘Harrow beauty’,
‘Kijowska wczesna’, ‘Jersey land’), are ideal for the manufacture of healthy dried snacks. Additionally, juicy peaches with a
high content of organic acids and bioactive compounds, i.e., ‘WB 258’, ‘Spring time’ and ‘Beta’, are suitable for the produc-
tion of purees, smoothies, and juices. Finally, it has been shown that peach fruit is an interesting raw material with a varied
chemical composition and nutritional value, strongly determined by the cultivar.
Keywords Prunus persica· Chemical composition· PCA· UPLC-PDA· HPLC-ELSD· Bioactive compounds
Introduction
Recently, the interest in the composition of fruits has grown
because of increased awareness of their possible health ben-
efits. This results from recent studies which demonstrate,
beyond any doubt, that fruits have a significant impact on
reduced morbidity and mortality from chronic non-commu-
nicable diseases’ society in the 21st century.
The benefits of eating fruit are mainly connected with
the richness of their chemical composition. Basic compo-
nents of fruits include protein, carbohydrate (especially fruc-
tose, sorbitol and glucose), minerals (Mg, Fe, P, Cu, Ca,
Na, K), vitamins (C, PP, B group, provitamin A), organic
acids, pectins and a lot of bioactive secondary metabolites of
plants (for example, isoprenoids and phenolic compounds)
[1]. The largest range of pro-health properties is attributed
to secondary metabolites (polyphenols, isoprenoids). Phe-
nolic compounds constitute a very numerous group of natu-
ral organic substances that occur in various morphological
parts of plants. They exhibit especially strong antioxidative
properties that protect defense systems of the body against
destructive effects of free radicals [2–4]. Another group
of secondary metabolites of plants that exhibit health-pro-
moting properties are isoprenoids that include triterpenes,
iridoids, carotenoids and chlorophylls. They are, likewise
polyphenols, classified as both preventive and intervention
antioxidants, and are characterized by valuable biological
properties the best documented of which is their provitamin
activity [5].
The other pro-healthy benefits are also ascribed to other
compounds occurring in fruits, e.g., organic acids, pec-
tins, vitamins and minerals. The organic acids stimulate
the secretion of digestive enzymes and regulate the proper
chemical reactions of the body [6]. Pectin inhibits the
absorption of dietary fats and their collection in the tissues
* Paulina Nowicka
paulina.nowicka@upwr.edu.pl
1 Department ofFruit, Vegetable andPlant Nutraceuticals
Technology, Wrocław University ofEnvironmental andLife
Sciences, 37 Chełmońskiego Street, 51-630Wroclaw, Poland
2 Research Station forCultivar Testing inZybiszów
nearWrocław, 55-080KątyWrocławskie, Poland
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930 European Food Research and Technology (2019) 245:929–938
1 3
of the liver. In addition, they influence the lower blood
glucose levels and improves peristalsis [7]. While vitamins
and minerals are responsible for the proper conduct of bio-
chemical reactions and functioning of the human body [8].
Considering the above, it seems advisable to undertake
any actions ascribing to the global trend of analyzing and
promoting raw materials with a high nutritive value and
health-promoting properties. Hence, the aim of this study
was to determine the chemical composition of fruits of
different cultivars of Prunus persica L. Batsch with spe-
cial focus on polyphenols, carotenoids, sugars and organic
acids content. Sugars and organic acid, as the main sol-
uble constituents of peach fruit, have a major effect on
taste and represent an index of consumer acceptability.
In turn, modern consumers are increasingly interested in
their personal health and expect the foods to be not only
tasty and attractive but also safe and healthy, therefore
polyphenols and carotenoids content were also analyzed
in this study. In addition, the PCA model was applied to all
data to determine the most important variables that explain
the relationships between the twenty selected cultivars of
peaches and to identify the most attractive cultivars.
Materials andmethods
Plant material
Twenty cultivars of peach fruit were used in this study:
• Early maturing: ‘Harbinger’, ‘Kijowska wczesna’,
‘Spring time’, ‘Beta’, ‘Maycresh’, ‘Harrow diamond’,
‘Dixired’, ‘Candor’, ‘Harnaś’, ‘Sweet haven’, ‘WB
258’,
• Mid-early maturing: ‘Early Redhaven’, ‘SB6A–35’,
‘Jerseyland’, ‘BL6’, ‘Red Cup’, ‘Royalvee’,
• Late maturing: ‘Flamin Fury’, ‘Harrow Beauty’, ‘Madi-
son’ (Table1).
All of them were appropriate for food manufacturing
and were grown in Poland. The fruits were harvested at
the Research Station for Cultivar Testing in Zybiszów near
Wrocław (51°3′51.11″N, 16°54′43.56″E) and were col-
lected at “ready-to-eat” ripening stage. Immediately after
harvest, in fresh raw materials, the content of Vitamin C,
soluble solids, pectin, ash, pH, titratable acidity, and fruit
weight were measured. In turn, for the analysis ofpolyphe-
nolic compounds, organic acids, sugars and carotenoids,
the whole fruits were freezing with liquid nitrogen and
crushing them to homogeneous powder by laboratory mill
and after that freeze-drying them.
Physicochemical analysis
The soluble solids’ content was determined by a refrac-
tometer and expressed as °Brix, while the pectins’ content
was analyzed according to the Morris method described
by Pijanowski, Mrożewski, Horubała and Jarczyk [9] and
expressed as g/100g fruit. Total content of
l
-ascorbic
acid, ash and dry matter as g/100g was determined by
the PN norms—PN-90/A-75101/11, PN-90/A-75101/08,
PN-90/A-75101/03, respectively.
Determination ofsugar content byHPLC coupled
tolight scattering detector
A solvent for the analysis of sugar content and determi-
nation of sugar was prepared as previously described by
Nowicka, Wojdyło and Teleszko [10]. All determinations
were done in triplicate and results were expressed as
g/100g dm of peach.
Determination ofacids’ content byUPLC‑PDA
method
Obtained freeze-dried peaches (1g) were mixed with
50ml of redistilled water, and after that ultrasonificated for
15min, boiled for 30min and centrifuged for 10min. The
extracts were applied into the Sep-Pak C-18 and eluted by
water to give a sample solution for the estimation of acid
content. The analysis of acid content was carried out on
UPLC Acquity system consisting of a sample manager,
binary solvent manager, PDA detector. Empower 3 soft-
ware was used for data collection and integration of chro-
matograms. A 10µL sample was injected on the Supel-
cogel TM C-610H column (30cm × 7.8mm; Supelco,
Bellefonte, PA, USA). The elution was carried out at 30°C
under a isocratic flow using 1mM phosphoric acid solu-
tion at the flow rate of 0.5mL/min. Acid components were
identified by comparison with the standards. The calibra-
tion curves were prepared by plotting different concen-
trations ranging from 0.5 to 10mg/mL (R2 ≤ 0.9998) of
standards versus the area measurements in UPLC. Results
were expressed as g/100g dm of peach.
Analysis ofpolyphenol compounds
The quantitative analysis of total polyphenols by UPLC
was performed as described by Wojdyło, Nowicka,
Laskowski and Oszmiański [11]. The results were
expressed as mg/100g dm of peach fruits.
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931European Food Research and Technology (2019) 245:929–938
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Table 1 Nutritional and chemical components in different peach cultivars
WFW whole fruit weight (g), PFW pulp fruit weight (g), SFW stone fruit weight (g), DM dry matter (%), SS soluble solids (°Brix), MI maturity index, P pectins (g/100g), A ash (%), Vit C Vita-
min C (mg/100g)
ǂ Value ± SD are means of three repetitions; ǂMean values followed by different letters are statistically different at p≤0.05
Cultivars Date of harvest WFW PFW SFW DM SS MI P A Vit C
Harbinger July 1 64.0 ± 2.8e ǂ60.1 ± 2.5ef 4.0 ± 0.3f 11.2 ± 0.1l 10.1 ± 0.0m 15.8 1.1 ± 0.0efg 0.2 ± 0.1h 8.2 ± 0.2f
Kijowska wczesna July 1 84.4 ± 7.0de 77.2 ± 7.1def 7.2 ± 0.5cde 13.1 ± 0.2e 12.0 ± 0.0f 14.5 1.4 ± 0.0b 0.3 ± 0.0gh 12.0 ± 1.5bcd
Spring time July 1 60.1 ± 17.6e 56.4 ± 16.9f 3.6 ± 0.7f 10.8 ± 0.2m 10.1 ± 0.0m 18.7 0.9 ± 0.0i 0.4 ± 0.0gh 11.1 ± 2.1cd
Beta July 15 94.6 ± 7.8cd 88.3 ± 6.9cde 6.4 ± 1.0def 12.9 ± 0.0f 12.1 ± 0.0e 20.5 1.1 ± 0.1ef 0.4 ± 0.0de 11.2 ± 0.2cd
Maycresh July 15 109.2 ± 17.6bcd 104.7 ± 17.6bcd 4.5 ± 0.1ef 11.5 ± 0.1k 10.5 ± 0.1k 14.3 1.1 ± 0.0fgh 0.4 ± 0.1def 7.2 ± 0.3fg
Harrow diamond July 15 96.4 ± 6.1cd 91.6 ± 7.4cd 4.8 ± 2.0ef 10.7 ± 0.0m 9.9 ± 0.0n 14.8 1.0 ± 0.0ghi 0.5 ± 0.0cd 4.2 ± 0.5i
Dixired July 15 99.7 ± 9.9cd 94.8 ± 9.1cd 4.9 ± 2.6ef 12.2 ± 0.1i 11.1 ± 0.0j 20.6 1.2 ± 0.0def 0.5 ± 0.0bcd 7.9 ± 1.0fg
Candor July 15 119.3 ± 18.9bc 109.2 ± 19.8bcd 10.1 ± 1.1ab 12.7 ± 0.0h 11.1 ± 0.0j 24.1 1.2 ± 0.0de 0.5 ± 0.0ab 4.1 ± 0.7i
Harnaś July 15 113.0 ± 44.5bcd 105.5 ± 44.2bcd 7.5 ± 2.0cd 11.6 ± 0.0k 10.4 ± 0.0l 17.6 1.3 ± 0.1cd 0.3 ± 0.1gh 4.1 ± 0.7i
Sweet haven July 15 89.0 ± 7.0cde 83.7 ± 6.8def 5.3 ± 0.6ef 13.3 ± 0.1e 12.3 ± 0.1d 21.5 1.1 ± 0.0ef 0.4 ± 0.0de 4.9 ± 0.0hi
WB 258 July 15 111.3 ± 18.6bcd 101.1 ± 16.6cd 10.2 ± 3.2ab 11.9 ± 0.2j 10.4 ± 0.0l 15.5 1.3 ± 0.0cd 0.3 ± 0.0fg 13.6 ± 1.5b
Early redhaven July 27 114.1 ± 12.1bcd 105.5 ± 11.4bcd 8.6 ± 0.7bc 10.4 ± 0.1n 9.6 ± 0.1o 26.5 0.9 ± 0.0i 0.4 ± 0.0def 8.6 ± 1.5ef
SB6A-35 July 27 99.7 ± 15.7cd 94.0 ± 16.7cd 5.7 ± 1.3ef 10.3 ± 0.0n 9.0 ± 0.0p 13.2 1.0 ± 0.0hi 0.4 ± 0.0de 7.8 ± 0.9fg
Jerseyland July 27 140.3 ± 21.7ab 134.1 ± 22.3ab 6.2 ± 0.8def 14.3 ± 0.0b 13.1 ± 0.0b 16.4 1.4 ± 0.0b 0.5 ± 0.0abc 12.3 ± 0.2bc
BL6 July 27 111.1 ± 14.5bcd 107.2 ± 14.0bcd 3.9 ± 0.5f 12.8 ± 0.1gh 11.8 ± 0.0g 21.1 1.3 ± 0.2bc 0.4 ± 0.0ef 7.3 ± 0.1fg
Red cup July 27 160.2 ± 19.9a 148.2 ± 20.4a 12.1 ± 0.6a 12.3 ± 0.0i 11.4 ± 0.1i 20.6 1.1 ± 0.1ef 0.4 ± 0.0de 6.1 ± 0.2gh
Royalvee July 27 90.3 ± 3.2cde 84.8 ± 3.1def 5.6 ± 0.1ef 12.3 ± 0.1i 11.7 ± 0.0h 26.6 1.3 ± 0.1cd 0.4 ± 0.0ef 5.3 ± 1.1hi
Flamin fury August 23 100.2 ± 4.9cd 94.1 ± 5.6cd 6.2 ± 0.9def 14.1 ± 0.0c 13.0 ± 0.1c 19.9 1.3 ± 0.0cd 0.5 ± 0.0cd 10.2 ± 2.1de
Harrow beauty August 23 99.1 ± 20.9cd 92.3 ± 22.0cd 6.9 ± 3.2cde 15.7 ± 0.0a 14.4 ± 0.0a 22.9 1.6 ± 0.0a 0.6 ± 0.0a 16.3 ± 0.3a
Madison August 23 117.2 ± 5.4bcd 111.7 ± 5.2bc 5.5 ± 0.3ef 13.4 ± 0.1d 12.1 ± 0.0e 14.2 1.4 ± 0.0b 0.5 ± 0.0a 11.1 ± 0.2cd
Minimum 60.1 56.4 3.6 10.3 9.0 13.2 0.9 0.2 4.1
Maximum 160.2 148.2 12.1 15.7 14.4 26.6 1.6 0.6 16.3
Mean 103.7 97.2 6.5 12.4 11.3 19.0 1.2 0.4 8.7
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932 European Food Research and Technology (2019) 245:929–938
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Analysis ofcarotenoids
Determination of carotenoids by UPLC was prepared
as previously described by Wojdyło, Nowicka and
Bąbelewski [12]. The results were expressed as mg/100g
dm of peach fruits.
Statistical analysis
Results obtained in this study were analyzed and interpreted
using statistical methods, including principal component
analysis (PCA) to determine correlations, with the use of
Statistica ver. 12.50 software.
Result anddiscussion
Nutritional andchemical components indifferent
peach cultivars
In the present study, different physicochemical parameters
were evaluated in 20 cultivars of peach fruit including fruit
weight and contents of soluble solids, dry matter, pectins,
ash, and Vitamin C (Table1).
The average fruit weight was 103.7g, wherein 9 cultivars
were heavier and 11 were lighter. Among the analyzed peach
cultivars, the largest fruits were identified in ‘Red cup’ and
‘Jerseyland’ cv., weighing 160.2g and 140.3g, respectively.
In contrast, the smallest fruits were observed in the early
cultivars: ‘Spring time’—60.1g and ‘Harbringer’—64.0g.
Generally, the later cultivars of peach had heavier fruits than
those harvested earlier and vice versa. Other authors showed
that, except for the harvest time, fruit weight might also
depend on the cultivar of fruit, fruit load, and on climatic
and agricultural conditions [11, 13]. Although the early cul-
tivars ‘Harbinger’ and ‘Springtime’ were also characterized
by the lowest mass of the stones, the study showed no clear
relationship between harvest time and stone mass. Therefore,
it can be assumed that the size of stone is a cultivar-specific
trait.
Differences between peaches cultivars were also reflected
in the chemical composition of fruits. Dry matter content
of peach fruit ranged from 10.3% (‘SB6A-35’) to 15.7%
(‘Harrow Beauty’). Compared to the other fruits, the con-
tent of total solids was similar to that in apple (13–20%),
but definitely lower than in berry fruit, like chokeberry
(39.3–53.4%), blackcurrant (20.4–23.5%) or highbush cran-
berry (15.9–22.3%) [14, 15]. According to Zatylny etal.
[15], the content of dry matter depends on the cultivar, but
other authors showed that the total solid content might be
influenced by many factors like harvest time, degree of fruit
dehydration, an increase in the insoluble solids’ content of
the fruit during maturation or climatic and agricultural con-
ditions [13, 14].
The soluble solid content was also analyzed in this
study. It is a characteristic which largely determines the
final content of dry matter. Our study showed a relationship
between the content of soluble solids in the analyzed peach
fruits and their solids’ content. In the examined peaches,
the soluble solid content ranged from 9.0°Brix in ‘SB6A-
35’ to 14.4°Brix in ‘Harrow Beauty’, with the mean value
accounting for 11.3°Brix. This is consistent with findings
reported by Zhang, Peng, Zhang, Song and Ma [16] and by
Cirilli, Bassi and Ciacciulli [17] who showed the average
soluble solids’ content in peaches to reach 12°Brix. The
soluble solid content determined in our study in peach fruit
is similar to that determined in apricots (12.9°Brix), nectar-
ines (14.2°Brix) or apples (10.7–12.5°Brix), but definitely
lower compared to chokeberry (18.3°Brix) and blackcur-
rant (16.8°Brix). The soluble solids include: oligosaccha-
rides, polysaccharides, organic acids, dyes and tannins, and
other soluble compounds. Therefore, their content is usually
higher in strongly colored fruits containing more sugars and
acids.
In this study, we analyzed peach fruits also for the content
of ash, which depends not only on the species or cultivar, but
also on the growing conditions [18]. Among the analyzed
fruits, the highest content of mineral compounds was found
in fruits of ‘Harrow beauty’ (0.55%), ‘Madison’ (0.54%),
‘Candor’ (0.52%) and ‘Jerseyland’ (0.51%) cultivars. In
turn, ‘Harbringer’, ‘Kijowska wczesna’, ‘Spring time’, and
‘Harnaś’ cultivars had almost two times lower ash content
accounting for 0.28% on average. Ash content is basically
determined by minerals: magnesium, iron, phosphorus, cop-
per, calcium, potassium and sodium, which in fruits occur in
the form easily absorbable for humans [1].
Benefits that stem from fruit consumption are mainly
associated with the richness of their chemical composition,
including the contents of pectins and vitamin C. Pectins
inhibit the absorption of dietary fats and their deposition in
liver tissues. In addition, they contribute to blood glucose
level reduction and improve peristalsis [7]. In turn, vitamin
C is responsible for the proper course of biochemical reac-
tions and body functions and is classified as both preventive
and intervention antioxidants. In addition, it is characterized
by valuable biological properties, the best documented of
which is its provitamin activity [8]. In the peach fruits ana-
lyzed in our study, the content of pectins ranged from 0.9%
(‘Early redhaven’) to 1.6% (‘Harrow beauty’). Peach fruits
are considered to be very good sources of pectin, whose
content in these fruits is comparable to that in apple (0.9%),
Japanese quince (1.0%), and blackcurrant (1.7%) [15]. In
the case of Vitamin C content, it differed greatly in indi-
vidual peach cultivars, ranging from 4.13 to 16.28mg/100g
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933European Food Research and Technology (2019) 245:929–938
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of raw material. The highest ascorbic acid content (above
12mg/100g) was detected in ‘Harrow beauty’, ‘WB 258’
and ‘Jereseyland’ cultivars, while the lowest one (under
5mg/100g) in ‘Candor’, ‘Harnaś’, ‘Harrow diamond’ and
‘Sweet haven’ cultivars. This is in agreement with findings
reported by Gil, Tomas-Barberan, Hess-Pierce and Kader
[19], who determined from 3.6 to 12.6mg/100g of Vitamin
C in peaches. In addition, they pointed out that Vitamin C
was a cultivar-specific traits, which can also be observed in
our research.
Sugar andacid content indifferent cultivars
ofpeach
The analyzed peach fruits were also determined for sugar
and acid contents. Apart from determining the total content
of these compounds, in this study we analyzed the exact
profile of sugars and acids in different cultivars of peach,
and the results of these analyses were presented in Table2.
Both the total contents and individual profiles of these com-
pounds appear to be crucial in shaping the taste and degree
of sweetness of raw materials. Therefore, their detailed
analysis allows, at the first stage of the study, to identify the
best cultivars in terms of sensory properties.
Among the seven organic acids identified in peach
fruits, the major ones were: malic acid (31–52%) > quinic
acid (12–25%) > citric acid (2–25%) ≥ fumaric acid
(9–12%) > oxalic acid (< 1%) ≥ shikimic acid (< 1%) and
isocitric acid, but it was present in trace amounts and only in
three cultivars. The predominant organic acid in peach fruits
was malic acid, which is also confirmed by other authors
[20]. Generally, the analyzed cultivars can be divided into
two main groups in terms of malic acid content. The first
of these is peach fruits that contain more than 4g of malic
acid /100g dm (these were early and very late cultivars)
and the other ones were these with malic acid content lower
than 3.5g per 100g of dm (‘Dixired’; ‘Candor’, ‘Harnaś’,
‘Sweet haven’, ‘WB 258’, ‘Early redhaven’,‘Royalvee’, ‘Har-
row Beauty’). Such great differences in malic acid content
were not shown by other authors who demonstrated its con-
tent to remain stable both during growth and maturation of
the peach fruit [20]. The conducted study showed also a high
content of citric acid which ranged from 2.87g/100g dm in
‘Beta’ cv. to 0.19g/100g dm of ‘Harbringer’. Such a great
difference in its content may be due to the degree of fruit
maturity. It has been shown that fully mature peach fruits
have a lower citric content [21]. Although, the malic acid
followed by citric acid were the major organic acids of peach
fruit—representing more than 65% of the total acid content
determined; quinic, shikimic, fumaric, oxalic and isocitric
acids were also identified in the analyzed fruits. Especially
noteworthy are the last two acids (isocitric and oxalic acids),
which have been never before identified in peaches.
Generally, the total content of acids demonstrated in this
study (5.43g–13.92g/100g dm of peach) fits within the
range of values previously described in literature, but it
obviously depends on the origin, cultivar, harvest date and
degree of fruit maturation [20, 21].
Sugars represent the main component of fruit edible
quality by imparting sweetness being one of the attributes
influencing the degree of consumer satisfaction regarding
peaches. The intensity of sweetness depends on the total
sugar content as well as on the sugar profile. It is due to
the fact that the sweetening power of fructose, glucose and
sorbitol differs from that of sucrose (1.7-; 0.8- and 0.6-fold,
respectively) and therefore it is important to determine the
relative content of each individual sugar [17]. Our study
showed sucrose to be the predominant sugar in different cul-
tivars of peach fruit, accounting for approximately 58–74%
of the total sugars content. The other major sugars were:
fructose (7–14%) > glucose (5–12%) > sorbitol (3–10%).
High contents of sugars in peach were also confirmed by
other authors [17, 22], who demonstrated that the sucrose
content should be from 40 to 80%, that of glucose and fruc-
tose (in variable ratios) together from 10 to 25%, and that of
sorbitol around 10%. In addition, it is noteworthy to us that
in each analyzed cultivar the content of fructose was higher
than that of glucose. According to Robertson and Meredith
[23], high-quality peaches have lower contents of glucose
and sorbitol and a higher content of fructose compared to the
low-quality peaches. Generally, the total content of sugars
determined in this study ranged from 49.54g/100g dm in
the case of ‘Maycresh’ cv. to 73.66g/100g of ‘Madison’
cv. Similar values were previously reported for peaches by
other authors [17, 22]. In addition, the authors agree that
the total and individual sugar contents are strongly affected
by seasonal variability, climate, irrigation or crop load, in
contrast to the sugar profile which is relatively stable across
environments and genotypes [17].
Also, maturity index (MI) of fruits was analyzed in this
study (Table1). It determines the relationship between con-
tents of total soluble solids content and acids and is used to
classify fruits as sour (MI: 5–7), sour–sweet (MI: 17–24),
and sweet (MI: 31–98) [24]. In addition, the MI appears to
be a key factor responsible for the flavor and taste of fruit
[11]. In the analyzed cultivars of peach, MI ranged from
13.24 (‘SB6A–35’) to 26.59 (‘Royalvee’). It may thus be
concluded that most of the studied fruits were semi-sweet,
but the later varieties were a little bit sweeter than those
harvested earlier.
Quantification ofbioactive compounds indifferent
cultivars ofpeaches
Figure1 presents results of determinations of polyphenols
and carotenoids content in peach fruit. The average content
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934 European Food Research and Technology (2019) 245:929–938
1 3
Table 2 Organic acids and sugar content in different peach cultivars
ǂ Value ± SD are means of three repetitions; ǂMean values followed by different letters are statistically different at p ≤ 0.05
Cultivars Sugar content (g/100dm) Acid content (g/100g dm)
Fructose Sorbitol Glucose Sucrose Total Oxalic acid Citric acid Isocitric
acid
Malic acid Quinic acid Shikimic acid Fumaric
acid
Total
Harbinger 8.8 ± 0.0cǂ3.8 ± 0.1e 7.7 ± 0.0c 40.2 ± 0.0l 60.5 ± 0.16g 0.1 ± 0.0b 0.2 ± 0.0l nd 6.1 ± 0.1bc 1.9 ± 0.2d 0.02 ± 0.00e 0.8 ± 0.1de 9.1 ± 0.3ef
Kijowska
wczesna
10.1 ± 0.0b 6.1 ± 0.1b 8.3 ± 0.0b 33.9 ± 0.0t 58.4 ± 0.20i 0.1 ± 0.0b 2.3 ± 0.0c nd 6.4 ± 0.3ab 3.5 ± 0.0a 0.09 ± 0.00a 1.6 ± 0.0b 13.9 ± 0.3a
Spring time 5.5 ± 0.0l 2.4 ± 0.1n 4.3 ± 0.0l 41.3 ± 0.0j 53.4 ± 0.12o 0.1 ± 0.0a 1.3 ± 0.1f nd 6.6 ± 0.1a 2.3 ± 0.0c 0.08 ± 0.02ab 2.3 ± 0.5a 12.8 ± 0.7b
Beta 4.7 ± 0.0n 2.6 ± 0.1l 3.3 ± 0.0r 53.1 ± 0.0b 63.7 ± 0.11d 0.1 ± 0.0a 2.9 ± 0.0a nd 4.6 ± 0.1f 2.6 ± 0.0b 0.04 ± 0.01cd 1.2 ± 0.1c 11.4 ± 0.4cd
Maycresh 5.5 ± 0.1l 3.6 ± 0.1gh 3.6 ± 0.0p 36.8 ± 0.0s 49.5 ± 0.16p 0.0 ± 0.0cd 0.4 ± 0.0kl nd 5.8 ± 0.6cd 1.3 ± 0.0hi 0.02 ± 0.00e 0.9 ± 0.0de 8.4 ± 0.6f
Harrow
diamond
6.3 ± 0.0i 2.9 ± 0.0k 4.9 ± 0.0j 39.0 ± 0.0m 53.1 ± 0.15o 0.0 ± 0.0cd 0.8 ± 0.1ij 0.2 ± 0.1a 5.8 ± 0.1cd 1.2 ± 0.0hij 0.02 ± 0.00e 1.5 ± 0.1b 9.5 ± 0.3e
Dixired 4.1 ± 0.0p 1.5 ± 0.0p 2.7 ± 0.0s 47.2 ± 0.0e 55.5 ± 0.10lm 0.0 ± 0.0d 1.1 ± 0.1fgh 0.1 ± 0.0c 2.7 ± 0.1j 1.8 ± 0.5de 0.05 ± 0.00c 1.2 ± 0.3c 6.9 ± 1.0g
Candor 5.2 ± 0.1m 2.5 ± 0.0m 3.6 ± 0.0p 50.5 ± 0.0d 61.9 ± 0.15f 0.0 ± 0.0d 1.0 ± 0.0ghi nd 2.7 ± 0.0ij 1.6 ± 0.1ef 0.02 ± 0.01e 1.1 ± 0.1c 6.6 ± 0.2g
Harnaś 7.8 ± 0.0g 3.6 ± 0.1fg 6.9 ± 0.0d 40.6 ± 0.0k 58.9 ± 0.14h 0.0 ± 0.0d 1.2 ± 0.0fg nd 2.7 ± 0.0ij 2.0 ± 0.0d 0.03 ± 0.00de 0.7 ± 0.0ef 6.7 ± 0.0g
Sweet haven 5.8 ± 0.0j 3.5 ± 0.0ij 4.0 ± 0.0m 42.6 ± 0.0i 55.8 ± 0.14l 0.0 ± 0.0d 1.4 ± 0.1ef nd 3.1 ± 0.1hi 0.8 ± 0.0l 0.04 ± 0.00cd 1.0 ± 0.0cd 6.3 ± 0.2g
WB 258 8.0 ± 0.0f 3.7 ± 0.0f 5.2 ± 0.0i 38.4 ± 0.0n 55.3 ± 0.15m 0.0 ± 0.0e 2.5 ± 0.1bc nd 2.0 ± 0.1k 2.0 ± 0.0d 0.04 ± 0.00cd nd 6.5 ± 0.2g
Early red-
haven
5.6 ± 0.1k 3.4 ± 0.1j 3.8 ± 0.0n 44.6 ± 0.0h 57.3 ± 0.16j 0.0 ± 0.0cd 0.8 ± 0.7ij nd 3.4 ± 0.2h 1.4 ± 0.1ghi 0.04 ± 0.00cd 1.7 ± 0.1b 7.3 ± 1.1g
SB6A-35 5.8 ± 0.0j 2.4 ± 0.0n 4.3 ± 0.0k 46.3 ± 0.0f 58.7 ± 0.12h 0.1 ± 0.0b 2.7 ± 0.1ab 0.2 ± 0.0b 5.6 ± 0.5d 1.3 ± 0.0ghi 0.05 ± 0.01c 1.7 ± 0.1b 11.6 ± 0.8c
Jerseyland 7.8 ± 0.1g 3.4 ± 0.1ij 5.6 ± 0.0h 37.1 ± 0.0p 53.9 ± 0.21n 0.1 ± 0.0b 2.0 ± 0.1d nd 4.8 ± 0.1f 1.5 ± 0.1fg 0.03 ± 0.00de 0.6 ± 0.1ef 9.0 ± 0.3ef
BL6 4.4 ± 0.1o 2.1 ± 0.0o 3.7 ± 0.0o 52.2 ± 0.0c 62.3 ± 0.15e 0.1 ± 0.0c 0.6 ± 0.0jk nd 4.2 ± 0.2g 1.2 ± 0.1hij 0.02 ± 0.00e 0.7 ± 0.1ef 6.8 ± 0.4g
Red cup 6.7 ± 0.1h 3.9 ± 0.0d 5.7 ± 0.0g 36.9 ± 0.0r 53.1 ± 0.23o 0.1 ± 0.0c 1.3 ± 0.2fg nd 6.4 ± 0.1ab 1.4 ± 0.1fgh 0.07 ± 0.00b 2.2 ± 0.1a 11.4 ± 0.5cd
Royalvee 8.6 ± 0.0d 3.5 ± 0.0hi 6.1 ± 0.0e 38.0 ± 0.0o 56.3 ± 0.13k 0.0 ± 0.0d 0.9 ± 0.1hij nd 2.7 ± 0.0j 1.0 ± 0.1jk 0.03 ± 0.01de 0.8 ± 0.0de 5.5 ± 0.3h
Flamin Fury 10.3 ± 0.0a 7.4 ± 0.1a 8.4 ± 0.0a 46.3 ± 0.0f 72.4 ± 0.27b 0.0 ± 0.0cd 1.7 ± 0.0e nd 6.5 ± 0.1a 1.3 ± 0.0hi 0.05 ± 0.01c 1.0 ± 0.0cd 10.6 ± 0.1d
Harrow
Beauty
8.2 ± 0.0e 5.3 ± 0.1c 5.9 ± 0.0f 45.4 ± 0.0g 64.8 ± 0.20c 0.0 ± 0.0d 1.2 ± 0.1fgh nd 2.6 ± 0.0j 1.1 ± 0.1ij 0.02 ± 0.00e 0.5 ± 0.0f 5.4 ± 0.2h
Madison 7.8 ± 0.0g 6.1 ± 0.0b 5.7 ± 0.0g 54.2 ± 0.0a 73.7 ± 0.20a 0.1 ± 0.0c 1.4 ± 0.0ef nd 5.2 ± 0.2e 0.9 ± 0.1kl 0.03 ± 0.00de 0.7 ± 0.1ef 8.3 ± 0.5f
Minimum 4.1 1.5 2.7 33.9 49.5 0.01 0.2 0.00 2.0 0.8 0.02 0.5 5.4
Maximum 10.3 7.4 8.4 54.2 73.7 0.10 2.9 0.24 6.6 3.5 0.09 2.3 13.9
Mean 6.8 3.7 5.2 43.2 58.9 0.05 1.4 0.02 4.5 1.6 0.04 1.1 8.7
Content courtesy of Springer Nature, terms of use apply. Rights reserved.

935European Food Research and Technology (2019) 245:929–938
1 3
of polyphenols and carotenoids was 1732mg and 241mg
per 100g dm of peaches, respectively. The total content
of polyphenols differed significantly and ranged from
722mg/100g dm in ‘Madison’ to 3116mg/100g dm in
‘WB 258’. In the case of carotenoids, the highest content
was determined in ‘Harbringer’—390mg/100g dm of peach
fruit, while the lowest in ‘Spring time’—40mg/100g dm.
Positive correlations were found between the results of both
bioactive compounds—PC = 0.260.
Many factors influence the content of antioxidative com-
pounds. The most important is the cultivar, the morpholog-
ical part and the technological processes used during the
processing of the raw material. The appropriate agrotech-
nical practices and cultivation under appropriate climatic
conditions are also important [25]. In addition, the phyto-
chemical composition is largely conditioned by the process
of fruit ripening—a series of physiological, biochemical and
structural changes leading to obtain the full maturity fruits.
Belhadj etal. [26] confirmed that the content of bioactive
compounds depends on the degree of fruit maturity. Fruits
during the last stage of maturity (red peaches) were char-
acterized by three to ten times higher concentration of the
tested compounds than the unripe fruits (green fruits).
The presented study showed that the total carotenoids
and polyphenols content in peach fruits is significantly
dependent (p ≤ 0.05) on the cultivar. Differences between
concentration of carotenoids in different cultivars were also
demonstrated by Belhadj etal. [26]. The research of these
authors comprised four cultivars (‘Chatos’, ‘Elegant Lady’,
‘Gladys’, ‘Royal Glory’), which in full maturity were char-
acterized by the following content of carotenoids—523.92;
504.95; 263.20; 244.22µg βCE/g, respectively. In turn,
according to Bento etal. [27], the total polyphenol content
ranged from 22.4mg/100g dm to 134.2mg/100g dm. How-
ever, according to Nowicka etal. [28], peach puree contained
429mg/100g of product. The main reason for significant
differences may be the cultivar, cultivation method, climatic
conditions and the degree of fruit maturity—it was shown
that green peaches are a much better source of polyphenols
than partially mature ones [26]. The reduction of the total
content of the tested fruit compounds during maturation is
associated with an increase of polyphenol oxidase activity
[26; 29].
Principal component analysis ofdifferent cultivars
ofpeach fruits andtheir compounds
The PCA model was applied to all data to determine the
most important variables that explain the relationships
between the twenty selected cultivars of peaches and to
identify any group patterns (Fig.2). In addition, PCA was
carried out separately for early, mid-early and late maturity
cultivars of peach fruits.
Two principal components explaining 52% of the over-
all variance (31% and 21% for PC1 and PC2, respectively)
divided the analyzed cultivars into four distinct clusters.
The first principal component (PC1), which explains
31% of the overall variance, is clearly identified with the
MI, polyphenols, acid and ash content, while the second
principal component (PC2) is related to the carotenoids,
Vitamin C, pectins, sugar, dry matter content and physical
properties. The factors that most contributed to PC1 (posi-
tive side) were: MI, ash and polyphenols’ content, and
the organic acids to the negative side. On the other hand,
the main contributors to PC2 (negative side) were sugars,
0
1000
2000
3000
4000
WB 258
Kijowska
wczesn
a
Jersey land
Condor
BL6
Harrow
diamon
d
SB6A - 35
Harnaś
Dixired
Beta
Harrow
beauty
Early
redhaven
Harbinge
r
Royalvee
Spring m
e
Maycresh
Flamin fury
Sweet have
n
Red cup
Madison
mg/100 g dm
polyphenolscarotenoids
Fig. 1 Total content of polyphenols and carotenoids (mg/100g dm) in different cultivars of peach fruits
Content courtesy of Springer Nature, terms of use apply. Rights reserved.

936 European Food Research and Technology (2019) 245:929–938
1 3
vitamin C, pectins and dry matter, whilst carotenoids and
fruit size contributed to the positive side.
Thus, it was shown that the common feature for the
‘Jerseyland’, ‘Candor’, ‘Harnaś’, ‘WB 258’, ‘SB6A–35’,
‘BL6’ cvs. was the high content of polyphenolic com-
pounds and also maturity index and ash content. In addi-
tion, the PCA model showed that the early-maturing vari-
eties as ‘Kijowska wczesna’, ‘Harbringer’, ‘Spring time’,
‘Dixired’, ‘Maycresh’, ‘Harrow diamond’, and ‘Early red-
haven’ were characterized by a high content of vitamin C
and organic acids. In turn, the sweetest varieties, with the
highest mass of fruit and a high content of pectins were
the late-maturing cultivars: ‘Madison’, ‘Harrow beauty’,
and ‘Flamin fury’.
The PCA analysis carried out for the purposes of this
study thus confirmed significant differences in the chemical
composition of peach fruit depending on the cultivar. At the
same time, it indicated some common features of selected
cultivars, owing to which it is possible to divide the analyzed
peaches into more sweet ones, more sour ones or those with
a higher content of polyphenolic compounds.
Conclusion
The conducted study allowed for a very accurate analysis
of the physicochemical properties, including the content of
phytochemicals, in different cultivars of peach fruit grow-
ing in Poland. The analysis of the obtained results enabled
indicating differences between particular cultivars, as well
as identifying the most valuable peaches for both direct con-
sumption and processing. And so, the following cultivars
seem to be the most interesting from the point of view of
direct consumption: ‘Early redhaven’, ‘Candor’, ‘Harrow
beauty’ due to the large size of fruit, rich juiciness, high MI
index, as well as above-average content of polyphenols and
carotenoids as well as ‘WB 258’ with a slightly lower MI
index but a very high content of phytochemicals—polyphe-
nols, carotenoids and vitamin C. In turn, fruits with medium-
sized stones and fruits, a high content of dry matter and total
sugars, and with a high content of carotenoids—‘Harrow
beauty’, ‘Kijowska wczesna’, ‘Jersey land’, are ideal for the
manufacture of healthy dried snacks. Additionally, juicy
peaches with a high content of organic acids and bioactive
Fig. 2 PCA map showing the relationship among the physicochemi-
cal properties and analyzed peaches fruit. WFW whole fruit weight,
PFW pulp fruit weight, SFW stone fruit weight, dm dry matter, SS
soluble solids, MI maturity index, P pectins, Vit C Vitamin C, acids
total content of organic acids, sugars total content of sugar
Content courtesy of Springer Nature, terms of use apply. Rights reserved.

937European Food Research and Technology (2019) 245:929–938
1 3
compounds, i.e., ‘WB 258’, ‘Spring time’ and ‘Beta’, are
suitable for the production of purees, smoothies, and juices.
The PCA analysis carried out for the purposes of this
study thus confirmed significant differences in the chemical
composition of peach fruit depending on cultivar. At the
same time, it indicated some common features of selected
cultivars, owing to which it is possible to divide the analyzed
peaches into more sweet ones, more sour ones or these with
a higher content of polyphenolic compounds. Finally, it has
been shown that peach fruit is an interesting raw material
with a varied chemical composition and nutritional value.
Acknowledgements This work was supported by the Foundation for
Polish Science (FNP). Publication was supported by Wroclaw Centre of
Biotechnology, the programme The Leading National Research Centre
(KNOW) for years 2014–2018 and purpose subsidy 2017 (MNiSW) for
The Faculty of Biotechnology and Food Sciences, Wrocław University
of Environmental and Life Science.
Compliance with ethical standards
Conflict of interest The authors declare that there is no conflict of in-
terest.
Compliance withethics requirements The research does not in-
clude any human subjects and animal experiments.
OpenAccess This article is distributed under the terms of the Crea-
tive Commons Attribution 4.0 International License (http://creat iveco
mmons .org/licen ses/by/4.0/), which permits unrestricted use, distribu-
tion, and reproduction in any medium, provided you give appropriate
credit to the original author(s) and the source, provide a link to the
Creative Commons license, and indicate if changes were made.
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